This invention relates to a recording apparatus and a data control method therein, and more particularly to a data control technique for driving dot formation means in the recording apparatus.
In a recording apparatus such as a serial printer of impact dot type, thermal transfer type, etc., or a page printer of laser type, thermal transfer type, etc., for example, in an ink jet printer, a recording head is provided with dot formation means comprising a plurality of nozzle orifices, pressure generating chambers communicating with the nozzle orifices in a one-to-one correspondence, and pressure generating elements such as piezoelectric vibrators for pressurizing ink in the pressure generating chambers, thereby jetting ink drops from the corresponding nozzle orifices and a head driver circuit (drive means) comprising a plurality of switching elements for determining whether or not a drive signal is to be applied to the pressure generating elements based on record data, and ink drops are selectively jetted from predetermined nozzle orifices depending on which of the switching elements are driven, whereby predetermined recording is executed on a medium such as recording paper. Such record data is provided by expanding record information input from a printer driver in memory, as described with reference to FIG. 6.
In FIG. 6, record information created with a printer driver 96 installed in a personal computer is input to a printer via various interfaces for each page (step ST10). At this time, the one-page record information is stored as data in an input buffer 44A formed in DRAM (Dynamic Random Access Memory) by automatically switching the interfaces (step ST20). Next, a control section (CPU) executes command analysis on the data stored in the input buffer 44A one byte at a time and determines whether the data is record data or a record processing command (step ST30).
Next, the control section transfers the record data undergoing the command analysis to an image buffer 44B (first storage means) in the DRAM as image data (step ST40).
The image buffer 44B is configured corresponding to the head structure; for example, in a four-color printer comprising 96 nozzles per row, a recording head 10 is formed with nozzle orifices belonging to five groups (five rows) and thus the image buffer 44B is formed for as much as the five groups. The term xe2x80x9cnozzle orifices belonging to five groupsxe2x80x9d mentioned here refers to nozzle orifices belonging to three color groups for jetting three color inks of cyan (C), magenta (M), and yellow (Y), nozzle orifices belonging to a first black group (BK1) for jetting black ink on the monochrome recording and stopping jetting ink drops on the color recording, and nozzle orifices belonging to a second black group (BK2) for jetting black ink on the color recording and on the monochrome recording.
For example, one-pass data of nozzle #1 corresponding to the yellow (Y) group is transferred to the image buffer 44B in a raster direction (in the order of a, b, c) and after the data transfer concerning the nozzle #1 terminates, similar processing is repeated for executing data transfer concerning nozzles #2, #3, . . . #96.
Similar data expansion and transfer are executed for the nozzle orifices corresponding to the magenta (M) group, the cyan (C) group, the first black group (BK1), and the second black group (BK2).
When the image buffer 44B becomes full of the data, data of one word. (a and b rows in the image buffer) is transferred from the image buffer 44B to an output buffer 44C (second storage means) formed of SRAM (Static Random Access Memory) of a head control unit (step ST50). To do this, first the zeroth bit of one word is converted from raster into row from #1 to #96 and is serially transferred to a head driver circuit (step ST51). This operation is repeated 16 times, whereby one-word transfer is complete (step ST52). Similar transfer is also executed for other four groups. Then, an interrupt is generated and processing for the next one word is performed (step ST53). After this, such processing is repeated.
However, in the recording apparatus in the related art, serial conversion of the record data in the output buffer 44C and serial transfer to the head driver circuit are also executed for the nozzle orifices corresponding to a group jetting no ink drops and thus there is a problem of occurrence of fruitless processing time in the control section. That is, to execute color recording in the ink jet recording apparatus in the related art, serial conversion of the record data in the output buffer 44C and serial transfer to the head driver circuit are executed for all the five groups although recording is executed only with the nozzle orifices corresponding to the three color groups of cyan (C), magenta (M), and yellow (Y) and the nozzle orifices corresponding to the second black group (BK2) and no ink drops are jetted from the nozzle orifices corresponding to the first black group (BK1). Thus, with data indicating that no ink is jetted (xe2x80x9c0xe2x80x9d data) as record data, serial conversion in the output buffer 44C and serial transfer to the head driver circuit are executed for the first black group (BK1) not used for recording.
To execute monochrome recording in the ink jet recording apparatus in the related art, serial conversion of the record data in the output buffer 44C and serial transfer to the head driver circuit are executed for all the five groups although recording is executed only with the nozzle orifices corresponding to the first black group (BK1) and the nozzle orifices corresponding to the second black group (BK2) and no ink drops are jetted from the nozzle orifices corresponding to cyan (C), magenta (M), yellow (Y). Thus, serial conversion of the data indicating that no ink is jetted (xe2x80x9c0xe2x80x9d data) in the output buffer 44C as record data and serial transfer of the data indicating that no ink is jetted (xe2x80x9c0xe2x80x9d data) to the head driver circuit as record data are executed for cyan (C), magenta (M), and yellow (Y) not used for recording.
It is therefore an object of the invention to provide a recording apparatus and a data control method therein for making it possible to eliminate fruitless processing time and enhance throughput of recording by stopping serial transfer of record data for a group wherein the presence or absence of dot formation is fixed in all dot formation means.
In order to achieve the above object, according to the present invention, there is provided a recording apparatus comprising:
dot formation means being divided into a plurality of groups, each of the groups for forming a dot in accordance with a predetermined dot formation condition assigned thereto;
drive means for driving the respective groups in the dot formation means in accordance with record data;
for expanding record information into an image in storage means and for record data from the storage means to the drive means;
fixing signal output means for outputting a mode fixing signal determining whether the dot is formed or not, and for transmitting the mode fixing signal to the drive means associated with a group in the dot formation means in which whether the dot is formed or not is predetermined as the dot formation condition, instead of the record data;
mode fixing means for fixing the dot formation condition of the group in the dot formation means, to which the mode fixing signal is transmitted, as determined by the mode fixing signal.
In this configuration, drive control is performed based on the mode fixing signal for the group in which whether the dot is formed or not is predetermined in all dot formation means belonging to the same group. The mode fixing signal may be a signal via a hardware signal line or a software command. Thus, serial conversion to the record data and serial transfer of the record data to the drive means become unnecessary for the group subjected to drive control by the mode fixing signal, so that fruitless processing time can be eliminated. Therefore, as compared with the case where serial conversion to the record data and serial transfer of the record data to the head driver circuit are performed for all groups, fruitless data processing time and fruitless data transfer time can be eliminated, so that the throughput of recording can be enhanced.
For example, the fixing signal output means outputs a signal indicating that no dot is formed as the mode fixing signal to the drive means for the dot formation means belonging to the group not used for recording, and the mode fixing means fixes the dot formation means belonging to the corresponding group to a condition of forming no dots based on the mode fixing signal. In such a configuration, the fixing signal output means simply outputs the mode fixing signal for the group wherein no dots are formed in all dot formation means, whereby the mode fixing means fixes the drive condition in hardware assuming that no ink drops are formed for the dot formation means belonging to the group. Thus, serial conversion and serial transfer of the data indicating that no dot is formed (xe2x80x9c0xe2x80x9d data) as the record data need not be executed for the group of forming no dots, so that fruitless processing time can be eliminated.
In the invention, the storage means may comprise storage regions as many as the maximum number of groups having a possibility that they will be used at the same time or more. In this case, the control means reserves as many storage regions as the number of groups used for the current recording each time in the storage means.
In the invention, only as many storage regions as the maximum number of groups having a possibility that they will be used at the same time may be reserved as the storage means. In this case, the storage regions of the storage means are reserved only for the areas required for the record operation and thus in the control using the record data, the operation of forming dots by the dot formation means in all groups (for example, the flushing operation in an ink jet recording apparatus or the like) becomes impossible. In the invention, however, to form dots by the dot formation means belonging to all groups, if a signal indicating that a dot is formed is output for all groups as the mode fixing signal, ink drops can be jetted from nozzle orifices in all groups if the storage means is short of storage region.
In the invention, when the mode fixing signal is output and transfer of the record data becomes unnecessary and thus an excess storage region occurs in the storage means, preferably the control means uses the excess storage region for serial transfer of the record data.
In the invention, when the mode fixing signal is output and transfer of the record data becomes unnecessary and thus an excess storage region occurs in the storage means, preferably the control means uses the excess storage region for any other processing, such as a communication buffer.
In the invention, the dot formation means may be classified into color groups for a plurality of colors for color recording, a first black group for recording in black on the monochrome recording and stopping dot formation on the color recording, and a second black group for recording in black at both the monochrome recording time and the color recording time. In this case, the fixing signal output means outputs the mode fixing signal for the dot formation means belonging to the first black group on the color recording and outputs the mode fixing signal for the dot formation means belonging to the color groups on the monochrome recording.
In the invention, the fixing signal output means may output a signal indicating that a dot is formed by the dot formation means belonging to all groups to the drive means as the mode fixing signal, and the mode fixing means may fix the dot formation means belonging to all groups to a condition of forming a dot based on the mode fixing signal. In such a configuration, the operation of forming dots in all groups (for example, the flushing operation in an ink jet recording apparatus or the like) is possible if record data is not used.
In the invention, the drive means may comprise a shift register for converting the record data transferred in series into parallel form. In this case, the mode fixing means can fix the dot formation condition for the predetermined group to the condition defined by the fixing signal on a way of a signal transfer path from the shift register to the dot formation means.
In the invention, the drive means may comprise a shift register for converting the record data transferred in series into parallel form. In this case, the mode fixing means may cause the shift register to hold the data defined by the mode fixing signal.
From the viewpoint of a data control method for the invention, this method comprises the steps of:
providing a recording apparatus comprising dot formation means being divided into a plurality of groups, each of the groups for forming a dot in accordance with a predetermined dot formation condition assigned thereto; drive means for driving the respective groups in the dot formation means in accordance with record data; and for expanding record information into an image in storage means and for record data from the storage means to the drive means;
judging whether there is a group of the dot formation means in which whether the dot is formed or not is predetermined as the predetermined dot formation condition, when the record data is expanded in the storage means and is transmitted from the storage means to the drive means;
outputting a mode fixing signal determining whether the dot is formed or not, and transmitting the mode fixing signal to the drive means associated with the group in which whether the dot is formed or not is predetermined, instead of the record data; and
fixing the dot formation condition of the group in the dot formation means, to which the mode fixing signal is transmitted, as determined by the mode fixing signal.
In the invention, for example, a signal indicating that no dot is formed as the mode fixing signal is output to the drive means for the dot formation means belonging to the group not used for recording, and the dot formation means belonging to the corresponding group is fixed to a condition of forming no dots based on the mode fixing signal.
In the invention, a storage region may be reserved in the storage means only for the group for which the mode fixing signal is not output and reserving a storage region in the storage means may be skipped for the group for which the mode fixing signal is output.